# Cavity antiresonance spectroscopy of dipole coupled subradiant arrays

## TL;DR

This paper demonstrates how optimizing the geometry of dipole-coupled quantum emitter arrays within an optical cavity enhances light-matter interactions, especially for subradiant states, leading to significant collective effects observable through transmission spectroscopy.

## Contribution

It introduces a method to optimize emitter array geometry to significantly boost collective cooperativity and antiresonance signals in cavity quantum electrodynamics.

## Key findings

- Enhanced light scattering into the cavity mode by optimizing array geometry.
- Superlinear scaling of collective cooperativity with particle number.
- Detectable antiresonances in transmission spectroscopy.

## Abstract

An array of $N$ closely spaced dipole coupled quantum emitters exhibits super- and subradiance with characteristic tailorable spatial radiation patterns. Optimizing their geometry and distance with respect to the spatial profile of a near resonant optical cavity mode allows to increase the ratio between light scattering into the cavity mode and free space by several orders of magnitude. This leads to a distinct nonlinear particle number scaling of the relative strength of coherent light-matter interactions versus decay. In particular, for subradiant states the collective cooperativity increases much faster than the typical linear $\propto N$ scaling of independent emitters. This extraordinary collective enhancement is manifested both in the intensity and phase profile of the sharp collective emitter antiresonances detectable at the cavity output port via transmission spectroscopy.